plugins: Use emit_before_op for PLUGIN_GEN_FROM_MEM

Introduce a new plugin_mem_cb op to hold the address temp
and meminfo computed by tcg-op-ldst.c.  Because this now
has its own opcode, we no longer need PLUGIN_GEN_FROM_MEM.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
6 files changed